Impact of cardiac transplantation on kidney function: a single- center experience

The impact of renal failure on survival following cardiac transplantation

OBJECTIVE

Renal failure after cardiac transplantation is a common and serious complication. In this study we investigated the incidence and effects of renal failure on survival among patients who underwent cardiac transplantation.

PATIENTS

Eight patients underwent cardiac and one patient combined cardiac and renal transplantation. The mean age of the patients was 33 +/- 11.6 years (range, 17 to 51). On preoperative echocardiographic evaluation, the mean ejection fraction was calculated as 19 +/- 3.11% (range, 16% to 24%). One patient had compensated renal failure and one patient, dialysis-dependent renal failure. Hemofiltration was routinely used during the operations. Corticosteroids, cyclosporine, and mycophenolate mofetil were used for immunosuppression. Early renal replacement therapy was performed in patients with acute renal failure.

RESULTS

The incidence of acute renal failure was 55.5% (5 patients). In the early postoperative and follow-up periods, the mean ejection fraction was 55 +/- 9.9% and 57 +/- 4.5%, respectively. The mean follow-up period was 21.3 +/- 8.8 (range, 6 to 33) months. In the early initiation period, the mean peak value of cyclosporine blood level was 479 +/- 201.8 ng/mL during the first month, 250 +/- 95.3 and after the third month, 195 +/- 43.7 ng/mL. The mean creatinine level at last follow-up was 1.27 +/- 0.4. One patient experienced a grade III-A rejection episode. One patient died due to coronary artery occlusive disease at 31 months after transplantation.

COMMENT

In our study we have observed that renal failure had no negative effect on patient survival. This can be explained by improved cardiac performance, keeping cyclosporine levels low finding and utilizing early renal replacement treatment.

Renal protective strategies in heart transplant patients

PURPOSE OF REVIEW

Chronic renal failure associated with long-term calcineurin inhibitor immunosuppression is a substantial clinical problem in the heart transplant population, compounded by difficulties in identifying patients likely to develop renal dysfunction. Several approaches, however, have been developed or are being investigated to preserve renal function in heart transplant patients.

RECENT FINDINGS

Approaches to identify patients with an increased risk of developing renal dysfunction are being refined, and improved calcineurin inhibitor monitoring strategies are being investigated. Novel immunosuppressive regimens including mycophenolate mofetil and/or rapamycin that lack nephrotoxicity promise new therapeutic strategies with the efficacy of calcineurin inhibitor-based combinations. Temporary ('holiday') or permanent ('retirement') calcineurin inhibitor replacement with interleukin-2 receptor monoclonal antibodies has the potential to halt progressive renal dysfunction. Finally, emerging data on the renal protection afforded by angiotensin converting enzyme inhibitors and angiotensin II receptor blockers, either singly or in combination, provide another avenue of investigation.

SUMMARY

Several strategies have demonstrated their potential to preserve or improve renal function in heart transplant patients in small studies. Large randomized controlled trials are necessary to determine the optimal strategies to prevent rejection while preserving renal function in the long-term management of heart transplant patients.

The outcome of heart transplant recipients following the development of end-stage renal disease: analysis of the Canadian Organ Replacement Register (CORR)

End-stage renal disease is a significant complication of heart transplantation (HTx), but our understanding of dialysis outcomes in HTx recipients remains limited. We performed a retrospective analysis looking at dialysis mortality in HTx recipients as compared to a matched dialysis cohort. We also examined outcomes with respect to kidney transplantation (KTx) in these cohorts. 2709 incident HTx recipients were captured from the Canadian Organ Replacement Register between 1981 and 2002. The incidence of dialysis after HTx was 3.9% (n = 105) and carried a greater crude mortality compared to HTx recipients not requiring dialysis (56.2% vs. 35.9%, p < 0.001). Compared to the matched dialysis cohort, survival of HTx patients on dialysis was also significantly worse (19% vs. 40%, p = 0.003). In those receiving a KTx, survival did not differ between the two cohorts; however, in those that did not receive a KTx the survival was significantly lower in the dialysis post-HTx group compared to the matched dialysis cohort (15.7% vs. 35.2%, p < 0.025). Our analysis suggests mortality on dialysis following HTx is greater than would be expected from a similar dialysis population, and KTx may abrogate some of this increased risk. Attention should be placed on preventing chronic kidney disease progression following HTx.

The natural history of renal function following orthotopic heart transplant

BACKGROUND

The outcome of solid organ transplantation has dramatically improved after the introduction of the calcineurin inhibitor cyclosporine. With the increasing longevity of heart transplant recipients, the long-term effects of cyclosporine on renal function have become more evident. The natural history of kidney function following orthotopic heart transplant is not well defined and long-term follow up studies are scant.

METHODS

We conducted an observational study on patients who received a heart transplant at Saint Louis University Hospital between January 1, 1983 and December 31, 1988. Patients were followed up for 15 yr or until death whichever occurred first. In order to assess the effect of heart transplantation and cyclosporine exposure on long-term renal function we restricted the statistical analysis to patients who survived the first year post-transplantation.

RESULTS

A total of 68 patients received orthotopic heart transplants at Saint Louis University Hospital between 1983 and 1988. Forty-eight (71%) patients survived for more than 1 yr. All patients were treated with cyclosporine based triple immunosuppressive regimen, with gradual cyclosporine dose reduction over time. The mean duration of follow-up was 8 yr. The estimated GFR at 5 and 10 yr post-transplant were significantly lower than estimated GFR at baseline and 1 yr post-transplant. There was no significant difference between estimated GFR at 15 yr and estimated GFR at baseline or 1 yr post-transplant. The cumulative incidence of chronic renal failure (GFR < or = 29 mL/min/1.73 m2) at 5, 10 and 15 yr was 4.2, 10.4 and 12.5%, respectively (p < 0.05). The cumulative incidence of severe chronic renal failure (GFR < or = 15 mL/min/1.73 m2) at 5, 10 and 15 yr was 2.1, 8.3 and 8.3%, respectively. The mortality rate was 8, 37, and 52% at 5, 10, and 15 yr, respectively. The 10 and 15 yr survivors had an estimated GFR at 1 yr post-transplant that was significantly higher than the non-survivors. Age, pre-transplantation estimated GFR, pre-transplantation diabetes and pre-transplantation hypertension are risk factors associated with > or = 10 mL/min/1.73 m2 decrement in estimated GFR.

CONCLUSION

Heart transplant survivors beyond the first year post-transplant have a significant decrease in renal function and significant mortality observed over time. Age, pre-transplant GFR, pre-transplant diabetes and pre-transplant hypertension are important risk factors for decrement in renal function.

De Novo Immunosuppression With Sirolimus and Tacrolimus in Heart Transplant Recipients Compared With Cyclosporine and Mycophenolate Mofetil: A One-Year Follow-Up Analysis

BACKGROUND

Limited data exist regarding the safety and efficacy of sirolimus in combination with a calcineurin inhibitor in heart transplant recipients.

METHODS

From January 2001 to June 2002, 31 de novo heart transplant recipients (treatment group) received a combination of sirolimus, tacrolimus, low-dose rabbit antithymocyte globulin, and glucocorticoids. Outcomes, such as actuarial survival, rate of rejection, incidence of infection, probability of developing diabetes mellitus, renal function, platelet and white blood cell counts, and incidence of coronary artery disease at 1 year, were compared with a cohort of 25 patients (control group) who underwent transplantation primarily in 2000 and in early 2002 treated with cyclosporine, mycophenolate mofetil, and glucocorticoids. All patients were followed up for at least 12 months.

RESULTS

Kaplan-Meier actuarial 1-year survival rates were equivalent between groups (97% for the treatment group and 88% for the control group), as was freedom from allograft rejection (48% and 42% for treatment and control groups, respectively). No cases of transplant arteriopathy were noted within the first posttransplantation year. Renal function was not significantly affected in either group. There was a striking increased incidence of mediastinitis in the treatment group (19%) versus 0% in the control group (P = .02). Tacrolimus-sirolimus therapy was associated with a nearly 11-fold increased incidence of new-onset diabetes mellitus as well (P = .004).

CONCLUSION

Tacrolimus, sirolimus, and steroids (following low-dose rabbit antithymocyte globulin) were associated with an increased incidence of mediastinitis and posttransplantation diabetes mellitus. No obvious long-term benefit on survival, arteriopathy, or renal function was noted.

Preservation of Renal Function After Heart Transplantation: Initial Single-Center Experience With Sirolimus

BACKGROUND

Long-term survivors of heart transplantation are often confronted with chronic kidney disease, by definition related to the intake of calcineurin-inhibitors. Sirolimus is increasingly proposed as an alternative immunosuppressive agent due to its absence of nephrotoxicity.

METHODS

Between November 2002 and November 2003, 9 adult heart transplant candidates with moderate to severe chronic renal disease were switched from cyclosporine to sirolimus. The conversion scheme consisted of an immediate stop of cyclosporine and an 8-mg loading dose of sirolimus, followed by 3 mg/d; after 1 week, the sirolimus dose was adjusted to maintain trough levels between 5 and 15 microg/L. The majority of patients were on corticosteroids, and on either azathioprine or mycophenolate mofetil. At conversion, the mean serum creatinine level was 2.11 (+/-0.4) mg/dL and the mean glomerular filtration rate (GFR) was 32 (+/-7) mL/min/1.73 m(2). Prior to conversion, the renal dysfunction was predominantly stable.

RESULTS

After conversion, there were 7 dropouts (75%) due to several side effects related to sirolimus: edema (n = 2), general discomfort (n = 2), delayed wound healing (n = 1), cardiac thrombus (n = 1), and diarrhea (n = 1). The median treatment time with Sirolimus, therefore, was only 4.0 months. While on sirolimus, the renal function of all patients remained unchanged or showed even some improvement. Retrospective nephrological review revealed severe renal artery stenoses in 2 patients and serious generalized abdominal and renal atheromatosis in 7 patients. No cardiac dysfunction was seen.

CONCLUSION

Conversion from cyclosporine to sirolimus was problematic due to sirolimus side effects, occurring at any time after the switch. One should also question whether chronic kidney disease after heart transplantation is routinely caused by the administration of calcineurin-inhibitors, in view of the generalized renal and abdominal atheromatosis.